Pump inlet strainer



March 24, 1970 L. F. KOHLBERG PUMP INLET STRAINER Filed Dec. 18, 19s? Lama. F 5%,,

Q" w t? United States Patent 3,502,220 PUMP INLET STRAINER Lawrence F. Kohlberg, 4332 Kay Lane, Alfton, Mo. 63123 Filed Dec. 18, 1967, Ser. No. 691,504 Int. Cl. B01d 29/20 US. Cl. 210-416 4 Claims ABSTRACT OF THE DISCLOSURE A strainer is disclosed for use at the inlet of a pump to which liquid is provided through a supply pipe which extends transversely to the pump inlet. Liquid is admitted through the side of a substantially cylindrical chamber which is of larger diameter than the pump inlet. The liquid passes substantially radially outwardly through the peripheral straining surface of a substantially cylindrical strainer element and is then guided, by longitudinal fins extending inwardly into the chamber, to the outlet of the chamber. The outlet is funnel shaped and conducts the liquid into the pump without substantial turbulence.

BACKGROUND OF THE INVENTION This invention relates to pump strainers and more particularly to such a strainer which may be used when liquid is provided to a pump through a supply pipe extending transversely to the pump inlet.

In many pump applications, such as in cooling towers, the liquid to be pumped is conducted to the pump through a supply pipe which extends transversely to or perpendicular to the pump inlet. The turbulence caused by the change in flow direction just prior to entering the pump has frequently required the use of a straight section of pipe aligned with the pump inlet to permit the turbulence to dissipate before the liquid reaches the pump thereby preventing cavitation in the pump. This solution, however, requires a substantial amount of space around the pump and is therefore undesirable in modern urban constructions where space is at a premium.

SUMMARY OF THE INVENTION Among the objects of the present invention may be noted the provision of an inlet strainer which provides liquid to a pump inlet substantially without turbulence even though the liquid is supplied to the pump through a supply pipe which extends transversely to the pump inlet; the provision of such a strainer which is of compact construction; the provision of such a strainer which is efiicient in removing foreign matter from the liquid; the provision of such a strainer which may easily be cleaned; and the provision of such a strainer which is relatively simple and inexpensive. Other objects and features will be in part apparent and in part pointed out hereinafter.

Briefly, an inlet strainer according to this invention is particularly useful with a pump to which liquid is provided through a supply pipe extending transversely to the pump inlet. Means are provided which define a substantially cylindrical strainer chamber having a diameter which is greater than that of the pump inlet. The chamber defining means is provided with a laterally facing in let which opens into the chamber near one end thereof and which is adapted for connection to the supply pipe. The chamber defining means is also provided with a generally funnel-shaped outlet for coupling the other end of the chamber to the pump inlet, the pump inlet and the chamber being generally in axial alignment with each other. A plurality of longitudinal fins extend inwardly into the chamber from the chamber defining means and a strainer member or element of generally circular cross section fits within the fins between the chamber inlet and the funnel-shaped outlet. The strainer member has a pcripheral straining surface. Accordingly, liquid entering the chamber through the inlet passes substantially radially outwardly through the straining surface, is then guided by the fins to flow longitudinally along the outer portions of the chamber, and then passes through the funnelshaped outlet into the pump inlet without substantial turbulence.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view, with parts partially broken away, showing an inlet strainer according to this invention installed between a pump and a supply pipe extending transversely to the pump inlet; and

. FIG. 2 is a section on line 22 of FIG. 1.

Corresponding reference characters indicate corresponding parts throughout the several views of the draw- 1ngs.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 there is indicated at 11 a centrifugal pump of generally conventional construction having a generally disk-shaped housing 13, an inlet 15 which opens substantially into the center of the housing 13, and an outlet 17 which emerges from the housing 13 substantially tangentially thereto. A pipe 19, through which liquid is supplied to the pump, extends generally parallel to the pump outlet, that is in a direction which is transverse or perpendicular to the pump inlet 15. The supply pipe 19 is connected to the pump inlet 15 through an inlet strainer designated generally as 21.

Strainer 21 includes a housing 23 which defines a substantially cylindrical strainer chamber 25. Chamber 25 is of substantially larger diameter than the pump inlet 15. The housing 23 also includes a substantially funnelshaped outlet portion 27 by means of which the chamber 25 is connected with the pump inlet 15 in axial alignment therewith. The strainer outlet portion 27 and the pump inlet 15 are provided with mating flanges 29 and 31 which are fastened together by means of bolts 33. Housing 23 also includes a laterally facing inlet portion 35 which is adapted for connection to the supply pipe 19 by means of mating flanges 39 and 41 on the inlet and the supply pipe respectively. The inlet opens into the strainer chamber 25 near the end thereof which is opposite the funnel-shaped outlet 27.

A plurality of longitudinal fins 43-46 extend inwardly into the chamber 25 from the housing 23 between the inlet and the outlet. Within fins 43-46 fits a strainer element constituted by a strainer bucket 49 which is of generally cylindrical shape, that is, it is of circular cross section. The strainer bucket 49 comprises a cylindrical straining surface 51 constituted by a perforate or screenlike material which is suitable for removing foreign objects from a liquid stream passing therethrough. A solid end cap 53 blocks liquid flow at the end of the cylindrical straining surface. The area of the straining surface is preferably substantially larger than the cross-sectional area of either the pump inlet 15 or the supply pipe 19.

Each of the fins 4346 includes a small inwardly projecting portion 54 adjacent the funnel-shaped outlet 27 and these projecting portions 54 abut the end cap 53 of strainer bucket 49 to prevent movement of the strainer bucket toward the pump inlet 15.

A collar or flange 55 extends inwardly from housing 23 into the chamber 25 and fits closely around the peripheral straining surface 51 of strainer bucket 49. The strainer bucket in turn includes a lip 57 which rests against the collar or flange 55. The collar or flange 55 and the lip 57 are disposed at an oblique angle to the axis of the chamber 25 with the portion of the flange 55 which is nearest the outlet 27 being on the side of the chamber which is nearest the inlet 35. Thus, liquid entering strainer 21 through the supply pipe 19 is directed naturally into the interior of the strainer bucket 49 and is blocked from passing between the strainer and the housing wall by the flange 55 and the lip 57.

The end of chamber 25 Opposite its outlet 27 is closed by a removable cap 58 which is secured to a mating flange 59 on housing 23 by bolts 61. The strainer bucket 49 is provided with a handle loop 63 which facilitates removal of the strainer bucket through that end of the chamber for cleaning.

The operation of the pump inlet strainer 21 is substantially as follows: Liquid entering the strainer through supply pipe 19 passes first into the interior of the strainer bucket 49. The turbulence created by the change in flow direction just prior to entering the strainer bucket is largely broken up by being strained through the peripheral Wall 51 of the strainer bucket, this surface being of relatively large area as compared with the cross section of either the pump inlet or the supply pipe 19 so that the flow velocity at the straining surface is relatively low. After passing substantially radially outwardly through the peripheral straining surface 51, the fluid flow is guided longitudinally of the chamber 25 through the longitudinal passages defined by the fins 43-46 on the Outside of the strainer bucket into the funnel-shaped outlet 27. There the flow is converged into the pump inlet 15 without substantial turbulence and, accordingly, the pump can operate properly without cavitation. It can thus be seen that the inlet strainer 21 both changes the direction of fluid flow in a very compact space and also strains the liquid so as to remove foreign objects Without introducing such turbulence as would disturb the operation of the pump 11.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A strainer for connection to the inlet of a pump, for straining liquid supplied to the pump via a supply pipe extending transversely to said pump inlet, said strainer comprising a housing defining a substantially cylindrical strainer chamber of larger diameter than the pump inlet, said housing having a funnel-shaped outlet at one end thereof constituting its inner end for connection to the pump inlet and having a removable closure at its outer end,

a flange extending inwardly from the housing into said chamber intermediate the ends of the housing, said housing having a lateral inlet between its said outer end and said flange for connection of said supply P P a plurality of fins extending inwardly from the housing into the chamber and extending longitudinally of the housing from said flange toward the inner end of the housing, there being at least three such fins,

a cylindrical strainer element fitted in said flange and said fins and extending longitudinally in said chamber from said flange toward the outlet end of said housing, said element being centered in said housing by said fins, and said fins defining longitudinal passages on the outside of said strainer element,

said strainer element being closed at its end toward the inner end of the housing and open at its other end, whereby liquid entering the housing through the lateral inlet of the housing flows through the cylindrical strainer element past the flange and then radially outward through the strainer element to the said longitudinally extending passages on the outside of the strainer element and thence longitudinally through said passages to said funnel-shaped outlet.

2. A strainer as set forth in claim 1 wherein each fin has an inwardly projecting portion adjacent the inner end of said strainer chamber engageable by the closed end of said strainer element.

3. A strainer as set forth in claim 2 wherein the strainer element has a lip at its outer end engageable with the flange.

4. A strainer as set forth in claim 3 wherein the flange and said lip are in a plane at an oblique angle to the axis of said chamber, the portion of the flange nearest the inner end of the housing being on the side of said chamber nearest the lateral inlet of the housing.

References Cited UNITED STATES PATENTS 1,348,536 8/1920 Billings et a1 210-452 2,073,026 3/1937 Renfrew et al. 210-416 X 2,732,950 1/1956 Keight et al. 210437 X 2,915,188 12/1959 Buker.

3,053,389 9/1962 Rosaen et al.

JOHN W. ADEE, Primary Examiner US. Cl. X.R. 210--45'2 

